External modular device for autonomous regulation of the temperature of an enclosure

ABSTRACT

A modular device for temperate regulation to be associated with at least one storage enclosure. The device has a thermochemical system having a tank which contains a liquefied gas that, following evaporation, combines with a reactive product contained in a reactor. The device has a switching mechanism that brings the reactor compartment into communication with only the storage enclosure in order to heat the latter and, at the same time, brings the evaporator compartment into communication with the outside of the device; and brings the evaporator compartment into communication with only the storage enclosure in order to cool the latter and, at the same time, brings the reactor compartment into communication with the outside of the device.

The present invention concerns an external modular device for autonomous regulation of the temperature of an enclosure consisting of an isothermal container, particularly of the type intended for transporting heat-sensitive merchandise.

It is known that to ensure the cold chain for this type of enclosure, it is not enough to be able to produce cold, since during transport, the enclosure may become subject to low-temperature conditions requiring its heating. For example, this is the case for an enclosure containing heat-sensitive products for which it is essential to maintain them between 2° C. and 8° C. and which, during transport, are subject during a certain time to an exterior temperature of −10° C. and at another time to a temperature of 30° C., etc.

In a case in which the enclosure consists of a large-volume container, normally a refrigeration unit is used, the evaporator of which is capable of furnishing the enclosure with the negative calories necessary for its cooling, and which is also capable of furnishing the calories necessary for its heating, by causing hot compressed fluid to pass through the evaporator.

However, such a device, particularly for reasons of weight and size, can only be used for large-volume enclosures. Moreover, this system must be able to be permanently connected to a source of electrical energy, which of course complicates the question of its transport. Furthermore, the utilization of the evaporator as means of producing heat is only possible on certain types of refrigeration units. Finally, such devices can only function in cold production mode or heat production mode, while the changeover from one mode to the other presents the risk of creating a thermal shock that could harm the integrity of certain heat-sensitive products.

Moreover, these devices are normally integrated into the enclosures where the temperature is to be controlled, and constitute an inseparable assembly with said enclosures. It is therefore useful to be able to have a temperature regulation device that can be disposed on multiple types of containers, for example particularly in order to be able to match the power of the regulation device to the power required by the nature of the products transported and the weather conditions encountered during said transport.

An object of the present invention is to propose an external device for maintaining the temperature of an enclosure that can be mounted, possibly removably, on an enclosure, the internal temperature of which must be preserved at a given set value, which is totally autonomous from the energy point of view and which is capable of carrying out its regulation function irrespective of the exterior temperature profile to which the enclosure is subject; said device is also modular and adaptable to the enclosure to be regulated.

Thus, an object of the present invention is a modular device for autonomous regulation of the temperature to a specific set value, capable of being mounted on at least one storage enclosure. Said device is characterized in that it comprises a housing that contains a thermochemical system comprising a tank, possibly forming an evaporator, containing a liquefied gas capable, after evaporation, of being combined with a reactive product contained in a reactor, according to an exothermic thermochemical reaction, the reaction product obtained being capable of being regenerated by heating while releasing said gas according to a reverse thermochemical reaction, the reactor and the evaporator of the thermochemical system respectively constituting means of heating and means of cooling said enclosure, and being respectively disposed in a reactor compartment and an evaporator compartment, made in said housing, said device comprising switching means disposed in said housing and capable of:

-   -   placing the reactor compartment in communication with only the         storage enclosure in order to heat the latter, and at the same         time, placing the evaporator compartment in communication with         the exterior of the device,     -   placing the evaporator compartment in communication with only         the storage enclosure in order to cool the latter, and at the         same time, placing the reactor compartment in communication with         the exterior of the device.

Advantageously, the housing includes means of mounting on an enclosure. Said mounting means are not limited according to the invention. It can involve straps secured to the housing and which can be wrapped around the enclosure, hooks that cooperate with complementary means disposed on the outer surface of the enclosure or any other attachment means allowing the housing to be attached, preferably removably, to the enclosure.

In one embodiment of the invention, the device can include means capable of placing the reactor compartment and the evaporator compartment in communication with the storage enclosure at the same time.

The device according to the invention can include an intake duct and an outlet duct that will be capable of being connected respectively to an intake and an outlet of the reactor compartment and to an intake and an outlet of the evaporator compartment, said intake duct and said outlet duct being respectively capable of being connected to an outlet and an intake of said storage enclosure.

According to the invention, the reactor compartment and/or the evaporator compartment will include means capable of activating the circulation of the airflow passing through said compartments.

The reactor compartment will be able to include an intake valve and an outlet valve, each of which will be capable of holding an open position in which the reactor compartment will be in communication with the exterior and a closed position in which it will be isolated from the exterior, and the evaporator compartment will be able to include an intake valve and an outlet valve, each of which will be capable of holding an open position in which the evaporator compartment will be in communication with the exterior and a closed position in which it will be isolated from the exterior.

Furthermore, the device according to the invention will be able to include two reversing valves, namely an intake valve and an outlet valve that will be capable of holding three positions, namely:

-   -   a first position in which they will respectively place the         intake and outlet of the evaporator compartment in communication         with the storage enclosure,     -   a second position in which they will respectively place the         intake and outlet of the reactor compartment in communication         with the storage enclosure,     -   a third position in which they will be in a middle position and         will respectively place the intake and outlet of the reactor         compartment and of the evaporator compartment in communication         with the storage enclosure.

The device according to the invention can be disposed in the upper part or lower part of the storage enclosure. It can also be mounted between two storage enclosures, one of said enclosures being able to be connected to the reactor in order to be heated and the other being able to be connected to the evaporator to be cooled.

The device according to the invention may be disposed in such a way that its reactor compartment can be placed in communication with a first enclosure, and simultaneously, its evaporator compartment can be placed in communication with a second enclosure.

Advantageously, said reactor compartment is formed in such a way as to be placed in communication with said first enclosure and simultaneously, said evaporator compartment is formed in such a way as to be placed in communication with a second enclosure. Advantageously, the device comprises at least a first enclosure on which said housing is mounted. The housing can be mounted at the upper part of said first storage enclosure. Such an arrangement facilitates the mounting and removal of the device according to the invention on the enclosure; the device can be mounted or removed without moving the enclosure.

Advantageously, the device includes a second storage enclosure, said reactor compartment is placed in communication with said first enclosure and, simultaneously, said evaporator compartment is placed in communication with said second enclosure. By way of non-limiting example, one embodiment of the present invention will now be described, with reference to the appended drawing in which:

FIG. 1 is a graph representing an example of a profile of temperatures to which a container equipped with a device according to the invention can be subject during a transport operation,

FIG. 2 is a schematic view of a container equipped with a device according to the invention in a cold production mode,

FIG. 3 is a schematic view of the container and of the device according to the invention represented in FIG. 2 in a heat production mode,

FIG. 4 is a schematic view of the container and of the device according to the invention represented in FIGS. 2 and 3 in a mode of producing heat and cold at the same time,

FIGS. 5a to 5c are schematic views representing various modes of mounting the device according to the invention on a container.

The device according to the invention is designed to enable an enclosure containing heat-sensitive products to be maintained at a specific setpoint temperature T_(C) for a given period of time, irrespective of the climatic conditions to which said enclosure may be subject during transport, for example.

Represented in FIGS. 2 to 5 is an example of a container forming an enclosure 1 that is intended to contain heat-sensitive products 3 and that receives in its upper part an autonomous temperature regulation device 2 according to the invention.

Said device comprises a housing 22 (represented in broken lines in FIGS. 2 to 4) that contains a thermochemical system of a known type, which can be implemented with salts and various gases and which is essentially composed of a reactor 9 containing a reagent, in this instance manganese chloride, which is mixed and compacted with an expander binder consisting in particular of expanded natural graphite, the apparent density of which is preferably between 50 kg/m³ and 150 kg/m³ and the mass proportion of manganese chloride to the expanded natural graphite preferably being between 50% and 90%.

The terms “apparent density of the expanded natural graphite” designate the density calculated by the following formula for the compacted final product: (mass of natural graphite mixed with a given mass of the reagent in order to obtain the compacted product)/the volume of the element obtained by compacting the mixture of the aforementioned natural graphite mass with the aforementioned given mass of reagent.

The reactor 9 is in communication, under the control of a control valve 11, with a tank 13 in which is stored a specific gas, consisting of ammonia, said tank in this instance acting as evaporator.

The reagent and the gas are such that the reagent is capable, by an exothermic thermochemical reaction, during a so-called operating phase, of absorbing the gas, thereby generating a reaction product, and then to restore it by a reverse thermochemical reaction, during a so-called regeneration phase, when the reaction product is heated.

Thus, when the reactor 9 and the evaporator 13 are placed in communication, the liquid gas contained in the evaporator is vaporized, which absorbs a certain amount of heat, thereby being the source of cold production, and said gas is absorbed by the reagent, thus generating an exothermic chemical reaction, the reactor thereby being the source of heat production. Once the reaction is completed, when the reaction product contained in the reactor 9 is reheated, the gas absorbed by the reagent is released and is then condensed in the evaporator 13.

According to the invention, and as represented in the figures, the reactor 9 and the evaporator 13 are respectively disposed in separate compartments 10 and 14, the respective intakes 10 a and 14 a of which can be placed in communication with an intake duct 5 in communication with an outlet 5 a of the enclosure 1, and the outlets 10 b and 14 b can be placed in communication with an outlet duct 7 also in communication with an intake 7 a of the enclosure 1, under the control of a system of six distribution valves that are interlocked with each other under the control of a microcontroller, not represented in the drawing and thus explained hereinafter.

In the appended figures, one end of the intake duct 5 is able to be connected to the aforementioned intakes 10 a and 14 a, and the second end of the intake duct 5 is connected to the outlet 5 a made in the enclosure 1. Similarly, one end of the outlet duct 7 is able to be connected to the aforementioned outlets 10 b and 14 b ,while the other end of the outlet duct 7 is connected to an outlet 7 a made in the enclosure 1.

The reactor compartment 10 includes ventilation means 12 that provide the circulation of air from its intake 10 a to its outlet 10 b and drives said air via the outlet duct 7 into the enclosure 1. Similarly, the evaporator compartment 14 includes ventilation means 16 that provide the circulation of air from its intake 14 a to its outlet 14 b and drives said air via the outlet duct 7 into the enclosure 1.

The reactor compartment 9 includes an intake valve 17 a and an outlet valve 17 b, which are each able to occupy an open position in which the reactor compartment 10 is in communication with the exterior (FIG. 2) and a closed position in which it is isolated from the exterior (FIG. 3).

Similarly, the evaporator compartment 14 includes an intake valve 19 a and an outlet valve 19 b, which are each able to occupy an open position in which the evaporator compartment is in communication with the exterior (FIG. 3) and a closed position in which it is isolated from the exterior (FIG. 2).

The system also includes two reversing valves, namely an intake valve 21 a and an outlet valve 21 b, which are able to occupy three positions, namely:

-   -   a first position, represented in FIG. 2, in which they         respectively place the intake and outlet of the evaporator 13 in         communication with the enclosure 1,     -   a second position, represented in FIG. 3, in which they         respectively place the intake and outlet of the reactor 9 in         communication with the enclosure 1,     -   a third position, represented in FIG. 4, in which the valves are         in the middle position and respectively place the intake and         outlet of the reactor 9 and of the evaporator 13 in         communication with the enclosure 1.

In an example of utilization of the present invention, a product 3 contained in the enclosure 1 is to be transported internationally. Said enclosure must be maintained at a setpoint temperature T_(C) of 5° C. and will be subject to various changes in temperature during said transport.

Thus, in the present example, and as represented in FIG. 1, the container equipped with a temperature regulation device according to the invention is first transported from its warehouse where the temperature is 15° C. (period 1) to be loaded into the baggage hold of an aircraft in which the temperature drops rapidly and remains at about −20° C. for ten hours (period 2). Upon arrival, the container is placed outdoors for four hours at a temperature of 40° C. (period 3), and is then transferred into the freight zone of a hangar, where it remains for five hours at a temperature of 25° C. (period 4). It is then loaded into the baggage hold of another aircraft, where its temperature drops to −20° C. for five hours (period 5), then is transported to an outdoor temperature of −30° C. (period 6) to the place where it is received.

Under these conditions, during periods 1, 3 and 4, it is obviously necessary to cool the enclosure 1, and the microcontroller that controls the switching valves places them in the position represented in FIG. 2, i.e., the reversing valves 21 a and 21 b open the intake 14 a and the outlet 14 b of the compartment 14 containing the evaporator 13, and the valves 19 a and 19 b are in the open position so as to place the evaporator in communication with the enclosure 1 in order to cool said enclosure, and at the same time, the valves 17 a and 17 b are opened in order to place in communication with the exterior the intake 10 a and the outlet 10 b of the compartment 10 in order to evacuate into the atmosphere the heat produced by the reactor 9 during the thermochemical reaction.

Conversely, during the periods 2, 5 and 6, the enclosure 1 must be reheated, and to do this, the valves are placed in the position represented in FIG. 3, i.e., the reversing valves 21 a and 21 b open the intake 10 a and the outlet 10 b of the compartment 10 containing the reactor 9, and the valves 17 a and 17 b are in the closed position with respect to the exterior, so as to place the compartment 10 containing the reactor 9 in communication with the enclosure 1 in order to reheat said enclosure, and at the same time, the valves 19 a and 19 b are opened in order to place the evaporator 13 in communication with the exterior in order to evacuate into the atmosphere the cold generated by said evaporator.

According to the invention, in order to be able to fine-tune the temperature in the enclosure when the exterior temperature oscillates around the setpoint temperature T_(C) of the enclosure 1, the valves are placed, as represented in FIG. 4, in a position in which hot air and cold air are simultaneously sent into the enclosure 1. To do this, the reversing valves 21 a and 21 b are placed in the middle position and the intake valves 17 a and 19 a and the outlet valves 17 b and 19 b ensure communication of the intake and outlet of both the reactor and the evaporator with the enclosure.

Of course, any other mode of switching other than valves could be used according to the invention.

Thus, as represented in FIGS. 2 to 5 a, the regulation device according to the invention can be attached to the upper part of the enclosure 1. However, as represented in FIG. 5b , it can also be attached to the lower part thereof. The housing 22 is therefore either mounted upon or beneath the enclosure 1.

In another embodiment of the invention, the regulation device can also be disposed between two enclosures 1 and 1′, which presents the advantage of being able to send simultaneously hot air into one of the enclosures (enclosure 1) and cold air into the other enclosure (enclosure 1′). 

1. Modular device for autonomous regulation of the temperature to a specific set value, capable of being mounted on at least one storage enclosure, characterized in that it comprises a housing that contains a thermochemical system comprising a tank, possibly forming an evaporator and containing a liquefied gas capable, after evaporation, of being combined with a reactive product contained in a reactor, according to an exothermic thermochemical reaction, the reaction product obtained being capable of being regenerated by heating while releasing said gas according to a reverse thermochemical reaction, the reactor and the evaporator of the thermochemical system respectively constituting means of heating and means of cooling said enclosure, and being respectively disposed in a reactor compartment and an evaporator compartment made in said housing, and in that said device further comprises switching means disposed in said housing and capable of: placing the reactor compartment in communication with only the storage enclosure in order to heat the latter, and at the same time, placing the evaporator compartment in communication with the exterior of the device, placing the evaporator compartment in communication with only the storage enclosure in order to cool the latter, and at the same time, placing the reactor compartment in communication with the exterior of the device.
 2. Device according to claim 1, characterized in that it includes means capable of placing the reactor compartment and the evaporator compartment in communication with said first storage enclosure at the same time.
 3. Device according to claim 1, characterized in that it includes an intake duct and an outlet duct that are capable of being connected respectively to an intake and an outlet of the reactor compartment and to an intake and an outlet of the evaporator compartment.
 4. Device according to claim 3, characterized in that said intake duct and said outlet duct are respectively capable of being connected to an outlet and to an intake of said first storage enclosure.
 5. Device according to claim 1, characterized in that the reactor compartment and/or the evaporator compartment include(s) means capable of activating the circulation of the airflow passing through said compartments.
 6. Device according to claim 1 ,characterized in that the switching means comprises valves.
 7. Device according to claim 1, characterized in that the reactor compartment includes an intake valve and an outlet valve, each of which is capable of holding an open position in which the reactor compartment is in communication with the exterior, and a closed position in which it is isolated from the exterior, and the evaporator compartment includes an intake valve and an outlet valve, each of which is capable of holding an open position in which the evaporator compartment is in communication with the exterior and a closed position in which it is isolated from the exterior.
 8. Device according to claim 7, characterized in that it comprises two reversing valves, namely an intake valve and an outlet valve that are capable of holding three positions, namely: a first position in which they respectively place the intake and outlet of the evaporator compartment in communication with the enclosure, a second position in which they respectively place the intake and outlet of the reactor compartment in communication with the enclosure, a third position in which they are in a middle position and respectively place the intake and outlet of the reactor compartment and of the evaporator compartment in communication with the enclosure.
 9. Device according to claim 1, characterized in that said reactor compartment is formed in such a way as to be placed in communication with said first enclosure and in that, simultaneously, said evaporator compartment is formed in such a way as to be placed in communication with a second enclosure.
 10. Device according to claim 1, characterized in that it comprises at least a first enclosure upon which said housing is mounted.
 11. Device according to claim 10, characterized in that said housing is mounted at the upper part of said first storage enclosure.
 12. Device according to claim 10, characterized in that it includes a second storage enclosure, in that said reactor compartment is placed in communication with said first enclosure and, simultaneously, in that said evaporator compartment is placed in communication with said second enclosure. 